In the prior art, a general fringe projection profilometry can measure the 3D shape/profile of a non-transparent object. In addition, an interferometer can measure the thickness or a refractive index of the transparent object, but the measurement must be executed in a noise-isolated, vibration-free, and stable environment. If the surface has faults or flaws, the result will be false positives on the shape measurement.
Therefore, it is necessary to provide a system for measuring a transparent object by fringe projection to solve the above described problems.